Directive antenna structure



Feb. 4, 1947. H. LANGSTROTH DIRECTIVE ANTENNA STRUCTURE Filed April 2o,' 1942 3 Sheets-Sheet l INVENTOR HALL LANG ST ROTH ATTORNEY Feb. 4, 1947 H. LANGSTROTH 2,415,103 DIRECTIVE ANTENNA STRUCTURE s Sheets-Sheet 2 Filed April 20. 1942 FIGS 9 4 7 I III 3 a I 9 8 a EAJM m E m f 7 6 8 O 7 M M w. n 5 I... .l 7 a W n H |l 2 6 m I? 7 2 6 5 w a m 6 6 6 Q 1 a Q u| 6 I I 7 .IIILI a Q mvamok HALL LANGSTROTH BY fl /fl M ATTORNEY Feb. 4, 1947. H. LANGSTROTH DIRECTIVE ANTENNA STRUCTURE Filed April 20, 1942 3 Sheets-Sheet 3 FIGS 3 l 4 09 wm m 0 Q 5 6 m m 5 7 M nw%9 A.. 2 g 9 M l 6 m 96 6 w e 6 m 0 FIGJZ HG-II 53 52 5| 4s I30 I I24 I26 I I20 I27 INVENTOR HALL LANGSTROTH BY ATI ORNEY Patented Feb. 4, 1947 UNITED STATES PATENT OFFICE DIREGTIVE ANTENNA STRUCTURE Hall Langstroth, Hempstead, N. Y., assignor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of New York Application April 20, 1942, Serial No. 439,708

Claims. 1

This invention relates to radio scanning apparatus in the form of a directive antenna by which high frequency electromagnetic energy is either transmitted or received. More particularly the invention concerns the mechanism and structural arrangements provided for directing the antenna and causing the same to scan a cyclically repeated pattern in space of substantially rectangular cross-section.

In the embodiment of the invention shown in the drawings, the antenna structure or scanning apparatus includes a radiator of high frequency electromagnetic energy in the form of a wave guide and a reflector of the parabolic type which cooperates with the radiator. A suitable deflector is employed, in the instant case, to obtain the desired cooperation of the radiator and reflector. Other forms of radiators and reflectors may obviously be employed, however, without departing from the inventive concepts herewith disclosed. In accordance with the teaching of the invention the radiator and reflector of the apparatus are arranged to move together about a particular axis. The reflector is also arranged to move independently of the radiator about an axis at right angles to the axis about which both parts move. The extent of movement of the reflector of the structure about its independent axis defines the nod angle of the antenna and the height of the repeatedly scanned rectangular space pattern. The width of the pattern is defined by the length of the arc through which both the radiator and reflector move together.

One of the features of the invention resides in the arrangement of the radiator and reflector of the antenna by which the same are supported for movement about a common axis.

Another feature of the invention is contained in the provision of an intermittently effective means for changing the angle of nod of the refiector alone without interfering with the continuity of the joint movement of the reflector and radiator.

A further feature of the invention consists in the utilization of a separate control means for the reflector by which the apparatus scans a cyclically repeated space pattern of substantially rectangular cross-section at any of a number of different elevations.

Another feature of the invention is provided by a selective controlling means for positioning the antenna to scan at any desired one of the I number of obtainable different elevations.

scription when read in connection with the accompanying drawings, wherein Fig. 1 is a. side elevation assembly and part sectional view of a radio scanning apparatus constructed in accordance with the present invention.

Fig. 2 is a detail plan view reduced in scale of the reflector of the improved directive antenna. V

Fig. 3 is a part front elevation of the reflector showing the deflector plate preferably included in the present antenna structure.

Fig. 4 is a transverse sectional view showing in a diagrammatic form the shape of the space patterns scanned by the improved apparatus.

Fig. 5 is a detail vertical cross-section showing the mechanism contained within the casing structure illustrated in Fig. 1.

Fig. 6 is a sectional view taken on line 6-6, in Fig. 5.

Fig. '7 is a sectional view taken on line 1-1, in Fig. 5.

Fig, 8 is a view similar to Fig. 5 showing a modified form of control mechanism for the antenna.

Fig. 9 is a wiring diagram and schematic view illustrating the selective means for positioning the antenna to scan at a particular one: of the different scanning elevations at which it is operative.

Fig. 10 is a detail horizontal cross-section showing the arrangement of the relay illustrated in Fig. 9 in the casingof the apparatus.

Fig. 11 is a view similar to Fig. 5 illustrating a further modified form of the control mechanism of the present invention, and

Fig. 12 is a detail plan view of a portion of the mechanism illustrated in Fig. 11.

With reference to the drawings and particularly to Figs. 1 to 3, inclusive, the directive antenna illustratively' shown therein includes a means for radiating high frequency electromagnetic energy in the form of a radiator 20 provided, in the instant case, by a tubular wave guide. Means are also provided to cooperate with the radiator 20 for the purpose of reflecting the energy issuing therefrom and directing the same into space with as little loss as possible. As shown in the drawings, a parabolic reflector 2| may be employed in this connection. To assist in the transfer of energy between the radiator and reflector, a deflector as designated at 22 may also be employed. Such an element, as shown in the drawings, may take the form of a conducting plate which is positioned at the approximate focal point of the reflector and shown 3 mounted on the projecting open end of the Wave guide by means of a coupling piece 23 which is made of a suitable dielectric material. As shown, Wave guide is turned through an angle of 90 about its longitudinal axis as indicated at 24 for the purpose in the instant case of changing the plane of polarization of the electromagnetic energy from a vertical position toa horizontal position in which last named position the energy issues from the open end of the Wave guide. In

carrying out the provisions of the invention, it

will be noted that the radiator 2l1 or wave guide-- projects through a circular opening 25 in the reflector 2i so that the parts may be: mounted for relative movement with respect to one an-.

other as well as for joint movement with one another. I The supporting means for the reflector 2| includes a yoke 38 whose central portion 3-! is'suit ably fixed to a driving gear 32 which is mounted tomove or: oscillate about a vertical axis; A sector gear 33 which meshes with gear 32 provides the means for sweeping therefiector about its vertical axis of support as hereinafter more particularly described. As, shown in Fig. 2, the reflector is pivotally mounted about a horizontal axis by meansof suitable trunnions which; extend from the respective endsof the-yoke 30, the trunnions being journaled in bearing members 35 fixed to the rear frame of: the refiecton, The reflector is independently supported about its trunnion defined nod axis and" is positioned thereabout by means of a cooperatingbracketi 3'6 and translatively movable rod 31 whose top portion is constructedtocontainathrust bearing member 38. Therefiector is-aparaboloid whose. axis of symmetry is situated normal'to its nod axis by the supporting or mounting means of the antenna. The focal point offthe reflector. is along its axis of symmetry. The inwardly disposed face. of. the bracket 36-restsonthe bearing member 38 and is yieldingly retained against the member by means such as-,.springs39, Fig. 2. One end of the respective springs 39 employed. is connected to thefixedyoke 3B and the other end is suitably sccured-touthe rear face ofthe refiectorZ I. It will now be seen that theyoke-3il and reflector 2.! are movable-=togethen about the axis of the gear 32 and that the reflector is movable relative to the radiator-aboutan axisat right angles to the gear axis. Inaccordance with theteaching of the present invention, the reflector is arranged to move relative to the radiator about an axis that is normal-'to thevertical axis of' the antenna and to the axis of symmetry 'of-the reflector itself.

rectangular cross-sectional shape as the hereinbefore'describedwave guide (Iii-whose rearwardly extending-end; as viewed in Fig. l, is fixed to a -portion of the yoke 35 so that it moves with theyolre and =reflector as a unit about the'vertical axis of the;gea-r-32.- A concentric line is employed; in the-instantcase; to transfer energy 4 between the movable guide 20 and the fixed guide 25. The concentric line includes an inner conductor 26 and an outer conductor 2?, the same being arranged to transfer energy from one to the other of the wave guides 2i! and 25. The inner conductor 26 of the concentric line is pivotally mounted by means of the spaced bearings 28 so that the same is coaxially positioned' with relation to thegear 32 and rod" 3-1. Fixed outer conductor 21 is suitably connected directly to the wave guide 25. Impedance matching plungers 2.9- are provided to match the impedance of the respective guides with the respective energy radiatingor receiving portions of the concentric line. As shown, therectangular'wave guide 25 is fixed to a suitable mounting plate 40 by means of a bracket 41.

As shown in Fig. l, the sector gear 33 and rod 3l'are controlled by a mechanism enclosed within upper and lower connected casing parts indicatedsrespectively at;43:and 4.4, the mechanism being; driven: by. Wayof shafted aligning coupling 46:, a reduction:gearing-connection'in housing 41 and driving: motor. 48-. The motor 48 and housingz il are suitably fixed inposition on the side of the mounting piece 40. A housing for a solenoid control'unitifor'the mechanism is indicated in this figure-at 4'9:

With reference to Figs. 5;.61and-fl', the continuing rotative'movement of shaft. 45. is converted into oscillatory movement-of sector gear 33 by means of an eccentric cam. pieceiil, a connecte ing plate 5i, craniepin 52' and crank member 53 to which the gear33;isdirectly connected by Way of asuitably journaled stub shaft'fid. It will be understood that the movementof sector gear 33 results iniacorresponding movement of the driv ing gear 32: which inturn causes the reflector 2| andathe radiator Zit-to-oscillate. or, sweep between predetermined limitsiabout their common vertical axisiofi'support. Substantially the same driving mechanism is=employed to 'obtai'nthis joint movement of the antennaiparts in both modified forms of the invention showndnFigs. 8 and 11 and in which corresponding reference numbers are used toindicate the respective elements. In Fig. 8, both sector-gear-w and gear 32' are shown as covered'by a protective: housing 55 which in this instance is also utilized to-provide amounting for an extra bearing for. a stub-shaft 54. which is axially positionedwith relation tostub shaft 5s andcooperateswith: thesame. This view also includes an additional showing of the electrical arrangements provided by the improved scanner bywhich apotentiometer unit shown-generally at- 561aiscontrolled by a pulley and belt motion transmittingconnection indicated at Hand 58, the driving p-ulleyof which is coaxial with'and mounted to--move correspondingly with the gear 322 The particularly described mechanism for obtaining; the cooperative oscillatory motion of the radiati-ng'and'-reflectormeans of thescanner is illustrative only and other suitable mechanism may be employed for thispurpose without departingfromtheconcepts of theinventive subject matter herein disclosed:

With further reference to Figs. 5 and '7, the reflector2l is positioned about its horizontal or nod axis by means of rod 31 whose inwardly disposed end is provided with a roller which rests-on a cam defining surface 6|. The cam surface BI is incorporated in the upper-face of a pivotally mountedcontinuouslyrotating gear62 which mayalso be; moved axially'along its fixed stub shaft 6-3: Rod 31' is confined to travelinan per casing 43.

. follows.

' number of different elevations.

'axial'dire'ctionby means of a longitudinal slot 64 and acooperating fixed tongue 65 which extends from a'portion of a shelf 66 included: in the up- Gear 62 is rotated by means of the motor driven shaft 45 by way of a gear 61 which directly meshes with the same, the shaft 68 for gear 61 and the cooperating gears 69 and which are situated just above the shelf 66. Cam 6| operates intermittently to change the eleva- .tion of rod 31 or the nod angle of the reflector twiceduring each revolution of gear 62. Such movements are timed to occur at the respective .limiting positions of the oscillatory motion of the reflector and radiator as the same move together about their common vertical axis. The rod 31 .is cyclically raised at one of the limiting positions of.oscillatory motion and lowered at the other of such positions so that the antenna is adapted to scan a completed space pattern of substantially rectangular cross-section. The cam 6| is designed in the instant case to either raise or lower rod 31 sufficiently to obtain a change in the nod angle of the reflector by two degrees.

A complete cycle of operation of the scanning apparatus takes place in four successive steps and includes two separate movements about both the vertical and horizontal axis of support of the radiator and reflector. With reference to Fig. 4, the scanning movement of the antenna occurs as Selecting position I in the scanning rectangle A as a starting point in the operation for example, the reflector 2| and radiator sweep about their common vertical axis under the control of the gear 32 and sector gear 33 and the described mechanism for driving the same until position 2 is reached. During this described first movement of the apparatus, the roller 60 is situated in the raised portion of the cam defining gear surface 6| as shown in Fig. 5. As the gear 32 changes its direction of movement, the cam BI is effective to lower rod 3'! and consequently raise the position of the reflector 2| about its independent horizontal axis. This directs the antenna to the approximate position shown at 3 in Fig. 4. A return movement similar to the described first movement occurs as the third step in the cycle of operation of the apparatus. When position 4 is reached, cam 6| is then effective to cause the reflector 2| to nod in a downward direction and restore the same to its original or starting position I, the apparatus continuously repeating the described space pattern.

A separate mechanism is provided to control the antenna about the horizontal axis of the reflector so that scanning operations of the character described are effected at any of a desired This mechanism may exert its control through the rod 31 and gear 62 so that as shown in Fig. 4 space patterns such as shown at B and C may also be scanned by the apparatus. In this connection, in Figs. 5 and 7, gear 62 is shown as moving upon two spaced rollers situated to either side of the fixed stub shaft 63. Rollers raise or lower the gear 62 along the axis of shaft 63, the gear continuing to be driven by the elongated gear 61 with which it meshes. The rollers II are situated at one end of a bail 12 which is pivotally mounted at 13 on an extending part of the shelf 66 situated in the upper casing 43. A single roller 14 is provided at the other end of bail 12, the same engaging a rotatably mounted cam piece 15 and retained in I engagement therewith by a spring 16. A ratchet wheel 11 is situated on the same shaft as cam 15 and these parts are prevented from moving in a clockwise direction, as viewed in Fig. 5, by means of a pawl 18. The actuating member for the cam 15 includes a reciprocatingly mounted slotted plate 19 which is moved against the retention of holding spring by means of a rocker lever 8|, crank connection 82 and the plunger or armature 83 of a solenoid coil 84 contained in the housing 49. A holding pin 85 which projects laterally from the plate 19 engages the respective teeth on the ratchet and in cooperation with pawl 18 positively positions cam 15 about its axis. In operation, the coil 84 is momentarily energized from a suitable current source and the plate 19 is moved to the left as viewed in Fig. 5 against the holding action of spring 80, the pin 85 moving correspondingly. The actuating piece for the mechanism is formed by a slotted resilient plate 86 connected at one end of the same to plate I9. Plate 86 is effective upon the return movement of the plate under influence of spring 80, the forward face ofthe slot 81 engaging the then adjacent tooth of the ratchet wheel 11 and moving the wheel one tooth space in a counterclockwise di- C, respectively, of the cyclically repeating type described result from this additional controlling mechanism. In operation, the described type of cam 15 changes the elevation of scanning areas in .successive steps for example from pattern A to B to C to B and back to A. Obviously by altering the contour of the cam 15 various other systematic sequences and other elevations of the reflector may be obtained.

With reference to Fig. 8, a selective control mechanism is included to position gear 62 along its axis so that the reflector may be set at any one of its different elevations and the antenna positioned to scan a desired one of the patterns A, B or C shown in Fig. 4. In this figure, the

driving means for continuously rotating gear 62 is similar to that, hereinbefore described and shown in Fig. 5, The positioning mechanism for cam gear 62, in this instance, includes two rollers, one of which is indicated at 90 in Fig. 8, on which the bottom face of gear 62 rests. Rollers 90 are mounted at one end of a bell crank shaped yoke 9| which is pivoted at 92 in a suitable trunnion support located in the lower casing 44. The opposite end of the yoke includes a single roller 93 which engages the surface of an internal cam forming piece 94. Cam piece 94 is designed to have three positions of rest which through the yoke 9| elevate the gear 62 so that the antenna is adapted to scan either space pattern A, B or C shown in Fig. 4. Cam piece 94 is mounted upon a shaft 95 supported in upper and lower bearings 96 and 97, respectively and the shaft is independently positioned by means of a gear 99. Gear 98 is driven by a further gear 99 which. meshes with the same. Gear 99 is mounted on a sleeve 59!] mounted on a further shaft which last shaft is directly driven by shaft 45 by way of the gears I02 and I03.

Also with reference to Figs. 9 and 10, a ratchet wheel IE4 is mounted on shaft |0|, this wheel continually rotating with shaft |0| beingdirectly 7 driven .by 1 shaft 45. Motion is communicated srrom-ratchetwhee'l L04 to the sleeve. I I10 and gear 80 by means of 'alpawl Hl5vwhich ispivOtally mounted in-a discmember I06 which forms a .part of the sleeve. I Pawl. B05 is normally ineffective, being retained in an inoperative positionby means of a resilientlyrnounted: detent I01 which is-controlled by. an electromagnetic relay I08. When the relay-is energized, the detent I01 is -withdrawnfrorn'engagement with the pawl I05 --which then engages the ratchet wheel I04 :throughthe influence of the spring W9. A comple'te revoiutien of the ratchet mechanism is per- .mit-tedbeforetheipawl again-engages its disabling detent iiilr The selective control isobtained, in the present instance, .by means. of a control circuit by which the relay: I08 .is-energized to permit m'ore than one revolution of the ratchet wheel 15.0 5 in order to position the cam "95 as desired. In the position of the partsshown in Fig. 8,

can M and yok-e fil are in their lowermost position and consequently pattern A, Fig. 4 is be- -ing:*repeatedly scanned by the directive antenna.

With particular reference to Figs. 9 and 10, an illustrative form of relay I08 controllingcircuit isshown to include four normally closed push -type switch-es indicated at A, B, C and OFF, the "first three corresponding to the scanning patterns designated in like fashion in Fig. 4, and the LOFF switch being included to completely disable theselective control mechanism when desired. Each of the switches :except the OFF switch is -:grouped with a cam controlled resilient arm type of-switch asshown ate, 1) and respectively. These last named switches are-contained in a switch box HE] fixed to the bottom casing 44 and arecontrolled by a cam III mounted on an extending portion of shaft 95. Due to the selected gear ratio between gears 98 and'99, shaft 95 rotatesat one-third the speed of shaft It, so that the switches a, 13 and c are contacted by the cam Iii each time the ratchetmech-anism completes a revolution of its movement and the pawl tits is at a position in which it cooperates with detent iili. The switch box H2 for the switches 13, C, and OFFmay be incorporated in the instrument casing or be entirely-separate, as desired. :As shown in the diagrammatic circuit diagram in Fi 9, each of the push button type of switches utilized, when positioned outwardly, as are A, Biand the OFF in the illustration, closes a series circuit'which includes the closed contacts thereof,. switches a, b or c, the relay I08 and a suitable 'sourceof electrical energysuch as battery H5. Each of .the switches A, .B and C also includes two wipecontacts asshown at I I6 and l Ii? which momentarily close a separate parallel circuit .for the relay I03 and release pawl 105 to initiate the operation of the selective controL, In describing the operation of the circuit, it will be assumed that the apparatus was initially set to scan pattern A, in Fig. 4, in which the parts are positioned as. shown in Fig. 8. The operatordesiring to have the apparatus scan-pattern C, starts the controlling mechanism by pressing switch C inwardly to the position shown in Fig. 9. As contact 1 Il wipes past contact i I0, the circuit for the relay is momentarily'closed and detent i0? releases pawl 105 so that the motion of .shaft II is communicated to gear99for at least one revolution. This motion results in corresponding movement of the shaft 95 which as:noted travels at one-third of the speed of shaft IOI. When cam HI, :onshaft 95 has. moved to close switch b, the. pawl I: has reached azdetent 'l 01 coop- :8 eratingcpo'sition'. .Due; to the fact-:that switchiB cremains :closedand. 'swi-tchtbis :closed;by1:am:.l I I the 'relay circuit through the respective: switches ;.is aagain completediand the detent' I0'|1.is withdrawn fromrits pawl engaging position. "This permits a furthermovement .of the gear 991by the engaged ratchet mechanism which continues unti1 a .iurther J full revolution of. shaft I 0| has been completed. When this point is reachedpcam I liicloses the switch 0. However, inasmuch-as selectorswitch Ciis open, the circuit to thereby 'remainsfopenand the 'detent then engagesxthe Vend 'of pawl. I05 and .disengages the same: from theltatchet wheel i011. Cam 94 has consequently been set in a .position to raise oamgear .021 its ':max'imum designed. distance, inithei instant case, in which the antenna'scans pattern C in'Fig. 4, as

udesired. I

A modification of the selective controlling mechanism isi shown in-Figs. 1'1 and 12 in which ua lpositive connection is utilized to'positionirod 3i. .FIhe equivalent of gear cam 62 .isrprovided in this instance by a 'camplate'IZil the movementiof which :is communicated to rod 3'l by way ofrocker arm I2I. Cam plate I20 is .rotatably "mounted on a fixedistub'shait .I26 and is driven .:by shafted/by means of gears I'22,. I23., internal gear .5 2'4, axially movable gear I25 .whichmeshes with gear I'Z4Land the sleeve I27 fitted 'on' shaft 'i'26'which connects gear I25 an'd1ca'm plate I20. :Thermechanism for changing the axial position of cam .plate I20, in this instance, includesia fixed: tubular cam element I28 mounted on "shelf 06;, the cam surface.:of *whichconsists of 'a spiral groove indicated at 129 contained" in its circumferentialsurface. The follower for said tubular cam element-120 is provided byrxa rot-atably'po- 'sitio'ne'd member I30 whichfits telescopically. .over the: element 528 .andis movable axially with relation "to the same. It will be understood that .zaxialiimovement 'of member I30 is thereby 'communicated xdirectly'to gear I25 and .cam plate I126 through hearing I 3 I to effect: a corresponding .movemento'f theseparts. :Cam follower" member i310 includes a flanged portion which is con- :structed as "a gear|32 :and rotary movementof the 'member is derived from the gear which 5111631165? with the sameand is controlled as heremounted. one platform I35. situated in the lower casing filland situatediniequidistantly spaced :relation *EbOllththG -movable :cam fol-lower member SSE Themovable plungers for eachof the -switches a. Lb =andgc are actuated by a rounded cam surface I 3'! fixed to the periphery: of the .memberiifiLthe same functioni-ng in-the same type of controlling circuit :hereinbefore desc'ribedxin connection WithFigJ'Q.

As many? changes. could. be made in the above "construction arrd anany: apparently, widely dilier- .zent embodiments ofthisinventioncould be made swithoutiideparting s from the scopetthereof, it is .int'endedth'at all matter contained in the-above description. or "shown in the accompanying: drawing-:shall be interpreted :as 1 illustrative and; not -i-n-:a';limiting sense. r

r Whatisclaimed is: -g' v. ;1. #IFhe-method of scanninga; field ofview with a directive antenna which includes a relatively movable electromagnetic energy radiator and reflector therefor which consists in moving said radiator and reflector together about a first axis, moving said reflector alone about a second axis perpendicular to the first axis, moving said radiator and reflector together in a reverse direction about the first axis, and then moving the reflector alone in a reverse direction about the second axis to complete a scanning cycle of the antenna.

, 2. The method of scanning a field of view with radio apparatus including a relatively movable radiator and reflector which consists in sweeping said radiator and reflector together in one direction about a vertical axis, nodding said reflector alone about a horizontal axis, sweeping said radiator and reflector together in a reverse direction about the vertical axis, and then nodding the reflector alone in a reverse direction about the horizontal axis to complete a scanning cycle of the apparatus.

3. Radio scanning apparatus comprising a movable electromagnetic radiator, a reflector for said radiator having an axis of symmetry, means for mounting said reflector to move about a first axis with said radiator and to move about a second axis normal to the first axis relative to said radiator with the axis of symmetry of the reflector being situated normal to said second axis, means for moving said radiator and reflector together about said first axis, and automatic means, only effective intermittent of the movement of the radiator and reflector together, for moving said reflector alone about said second axis.

4. An apparatus as claimed in claim 3 in which said reflector is a paraboloid, the second axis of which is situated in oifset relation to the first axis.

5. A directive antenna, structure, as claimed in claim 11, including means for varying the position of the reflector about its horizontal axis, and means for selectively setting the reflector by said position varying means at a desired angle of nod.

6. A directive antenna structure comprising an electromagnetic energy radiator, a reflector for said radiator having an axis of symmetry, means for supporting said radiator and reflector for movement about a vertical axis, means for supporting said reflector for movement independent of the radiator about a horizontal axis situated in perpendicular relation to the axis of symmetry thereof, mechanism for oscillating said radiator and reflector together about said vertical axis and for intermittently nodding said reflector alone about said horizontal axis, means for varying the position of the reflector about its horizontal axis, and means for selectively setting the reflector by said position-varying means at a desired angle of nod.

'7. Radio scanning apparatus comprising radiating means, reflecting means for said radiating means, means for oscillating said radiating means and reflecting means together about a first axis, and means automatically effective only at the respective reversing positions of the oscillating means for nodding said deflecting means relative to said radiating means about a second axis normal to the first axis.

8. A directive antenna structure comprising a reflector having an axis of symmetry, a wave guide for conveying electromagnetc energy to or from said reflector, deflector means positioned to transfer energy between the guide and reflector, means for supporting said reflector and Wave guide to oscillate together about a vertical axis and to oscillate relative to one another about a horizontal axis, said supporting means situating the axis of symmetry of the reflector normal to the horizontal axis thereof, means for oscillating said radiator and reflector together about said vertical axis, and intermittently effective means for oscillating said reflector alone about said horizontal axis.

9. Radio scanning apparatus comprising a movable electromagnetic radiator, a reflector for said radiator, means for mounting said reflector to move about a first axis with said radiator and to move about a second axis normal to the first axis relative to said radiator, intermittently operable means for moving said radiator and reflector together about said first axis, and automatic means efiective only between the operations of said intermittently operable means for moving said reflector alone about said second axis.

10. Radio scanning apparatus comprising a movable electromagnetic radiator, a reflector for said radiator, means for mounting said reflector to sweep about a first axis with said radiator and to nod about a second axis normal to said first axis relative to said radiator, intermittently operable means for sweeping said radiator and reflector together about said first axis, and automatic means for nodding said reflector alone about said second axis between the operations of said sweeping means.

11. A directive antenna structure comprising an electromagnetic energy radiator, a reflector for said radiator, means for supporting said radiator and reflector for movement together about a vertical axis, means for supporting said radiator and reflector for movement relative to one another about a horizontal axis, mechanism for oscillating said radiator and reflector together about said vertical axis, and mechanism only effective upon reversal of the direction of operation of said oscillating mechanism for nodding said reflector relative to said radiator about said horizontal axis.

12. Radio scanning apparatus comprising radiating means, reflecting means for said radiating means, means for oscillating said radiating means and reflecting means together about a first axis, means effective at the respective reversing positions of the oscillating means for nodding said reflecting means relative to said radiating means about a second axis normal to the first axis, mechanism for varying the position of the reflector about its second axis, and means for selectively setting the reflector by said positionvarying mechanism at. a desired angle of nod.

13. High frequency scanning apparatus comprising radiating means, reflecting means for said radiating means, means for oscillating said radiating means and reflecting means together about a first axis, means operable upon reversal of direction of motion of said radiating means and reflecting means at one limit of travel thereof for moving said reflecting means relative to said radiating means about a second axis normal to said first axis and operable upon similar reversal of direction at the other limit of travel of said radiating means and reflecting means for moving said reflecting means relative to said radiating means about said second axis and in opposite direction, whereby said reflecting means and radiating means cyclically sweep out 2. rectangular pattern in space.

...-124. '"Apparatus ia's in claim :13, further :includingmeans for'adjusting the :position-of said pattern, including means for adjusting the average position of "said reflecting means about said second axis.

15. Radio "scanning apparatus comprising antenna rmeans including reflecting means and radiating means relatively movable to one 'anothergmeans for cyclicallyzswe'eping said-antenna meansover a rectangular pattern in space, and means for adjusting the position of "said pattern in space, including means for'acljusting thelaverage position of "said reflecting "means relative "to T2 said'radiating means during said -cyclic sweeping.

LANGSTRGIH.

REFERENCES CITED The following references are of record Tin the 2 file of this patent:

UNITED STATES PATENTS 'William's Sepx30, 194 1 

